refactored to make use of the ServiceType enum throughout backend and frontend for typesafety

backend/src/main/java/com/vaessl/app/connection/ConnectionService.java

@@ -12,7 +12,7 @@ import com.vaessl.app.exception.WrongServiceTypeException;
 @Service
 public class ConnectionService {
 
-    private final Map<String, ConnectionProvider> providerRegistry;
+    private final Map<ServiceType, ConnectionProvider> providerRegistry;
 
     private final ConnectionRepository cRepository;
 
@@ -48,7 +48,7 @@ public class ConnectionService {
         return new LoginResult(saved.getId(), response.expiresAt());
     }
 
-    public ConnectionStatusResponse getConnectionStatus(String serviceType, Long connectionId) {
+    public ConnectionStatusResponse getConnectionStatus(ServiceType serviceType, Long connectionId) {
         ConnectionEntity entity = cRepository.findById(connectionId).orElse(null);
         if (entity == null)
             return null;
@@ -57,7 +57,7 @@ public class ConnectionService {
         Instant expiresAt = (provider != null) ? provider.getTokenExpiry(entity) : null;
         boolean connected = expiresAt == null || expiresAt.isAfter(Instant.now());
 
-        return new ConnectionStatusResponse(serviceType, entity.getAppUrl(), entity.getUsername(),
+        return new ConnectionStatusResponse(serviceType.name(), entity.getAppUrl(), entity.getUsername(),
                 expiresAt, connected);
     }
 }